Once upon a time, I believed in fairy tales.
Later, during my software engineering education, I came across a fairy tale called "capabilties detection".
The tale's main content was that it would be possible for a software to query for available capabilities in some kind of backend.
The tale then went on to make the audience believe that the "X11 client" could offer different sets fo features depending on the available "extensions".
A different variant of the tale told about a mythical API called OpenGL, if I remember correctly after all those years it had something to do with three dimensional visualisation.
Unfortunately fairy tales do not last forever. :(
Ah, well, I am sure I'll find a new fairy tale to believe in soon enough.